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54 Materials Jan/Feb 2024 FDM AsiA | www.fdmasia.com

www.entuitive.com at the end of the building’s service life. Nevertheless, despite
its benefts, DfD is not yet a common practice, especially in
TCC structures.
This opinion paper contributes to the understanding and
promotion of DfD in TCC foors. The overarching aim is to
encourage the timber construction industry, policymakers,

and researchers to consider DfD as a mainstream approach
in construction, especially for hybrid structures, to achieve
sustainability goals in the built environment. This paper provides
insights into the importance of implementing DfD in TCC foors
the amount of waste that would otherwise be created during and its role in achieving the principles of a circular economy.
the demolition of these structures. For this, end-of-life scenarios for TCC foors based on the
Furthermore, by streamlining the segregation process of design and connection type are initially explored, and some of
salvaged materials, issues relating to waste management and the existing deconstructable connection systems that enable
disposal can be minimised. Another beneft of DfD is related the implementation of DfD in TCC foors are introduced. The

to the reusability of materials; in regular TCC foors, it can implementation challenges of DfD in TCC foors are then briefy
be time-consuming, labour-intensive, and extremely diffcult highlighted. Finally, a list of required actions to address these
to separate the timber, concrete, and connectors without challenges is proposed.
causing signifcant damage to them.
Therefore, the direct reuse of these materials might not be End-of-Life Scenarios for TCC Floors Based on the
easy. With DfD, however, the direct reuse could be streamlined Design and Connector Type
as it allows for easy separation and offers the potential to The preferred end-of-life scenario in DfD is to be able to reuse

proft from the salvaged materials that are recovered from the recovered materials in their original form, as this does not
the deconstruction phase. In addition, buildings in which require a considerable energy input. In this case, at least two
DfD principles have been considered in the design may offer reuse options could be considered for TCC foors as follows:
higher adaptability for any future change in use or repair that Reusing the TCC slab elements: one option could be to reuse
might be needed. the entire TCC foor slabs in new applications, provided that
The implementation of DfD is especially important in modern the foor slabs are easy to separate from the building frames.
forms of TCC structures in which a high volume of laminated This might be an especially good option in structures where
timber products with large cross-sections are used. To put this several TCC slabs are prefabricated and then transported to
into perspective, as an example, in the Olver Design Building, the construction site and installed side-by-side to form a larger

around 2052 m3 of the building elements are made with foor. If this option is chosen for a TCC foor, then it is not
various types of timber products, including glulam (GLT) and important if the TCC shear connectors are deconstructable or
cross-laminated timber (CLT); a large portion of this is used in not; however, the slab to post/column connectors should be
the form of fve-layer CLT–concrete composite foors. If future deconstructable in order to ease the deconstruction process.
structures use DfD, such a high volume of timber materials If the slab to post/column connectors are not deconstructable
could still provide a valuable, reusable resource that might (such as those in most existing TCC foors that are designed
be suitable for new structural or non-structural applications using traditional methods), the TCC slab can theoretically